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Improving the scientific basis of the Local Environmental Risk Assessment for Pesticides (LERAP) scheme and identifying the scope for further development leading towards European harmonisation - PS2034

There is an existing UK scheme, known as the Lerap scheme, which has operated successfully for a number of years to enable the protection of surface water from spray drift, whilst allowing farmers to reduce the size of a buffer zone according to the drift-reducing capability of the spray generation equipment. The potential of equipment to reduce drift is denoted by a ‘one, two or three star rating’ and can be assessed from either field or wind tunnel drift data. The majority of Lerap star ratings have arisen from wind tunnel assessments, largely because the smaller scale and controlled conditions allow the necessary data to be obtained in the most cost-effective and timely manner. There is scope to modify and extend the Lerap scheme, particularly with wider buffer zones and greater levels of drift reduction. There would also be benefits in moving towards harmonisation of the different European schemes for assessing drift reduction potential.

The current Lerap scheme has been compared with limited field data but there would be benefits from extending this comparison to demonstrate more transparently that the drift reduction determined from wind tunnel experiments can be mapped onto drift reduction in full-scale field conditions, and to identify the range of circumstances for which this drift reduction applies. It would also be beneficial to assess whether modifications to the Lerap protocol – either the measurement or subsequent analysis – would improve the correlation between wind tunnel and field data for a wider range of conditions. The ability to relate the Lerap scheme to field data is a necessary requirement for harmonisation with the different European schemes – if each scheme can successfully be mapped onto the same field data, (i.e. the drift reduction predicted from the scheme is the same as that measured in the field) then they can be deemed to be fundamentally equivalent, and harmonisation will be possible.

The work proposed in this project will contribute to the policy areas of Environmental fate and behaviour and Specific policy support and will inform any future reviews or revisions to the Lerap scheme that CRD may undertake.

Project objectives are:
To relate wind tunnel measurements of drift reduction to the levels of drift reduction that are achieved under field conditions,
To revise the measurement and analysis methodology to allow greater flexibility;
To consider the options for harmonisation with other European drift-reduction schemes.
This will be undertaken through a review and re-analysis of existing data, combined with new data obtained in targeted wind tunnel studies.
General aims:
To relate wind tunnel measurements of drift reduction to the levels of drift reduction that are achieved under field conditions
To make improvements to the Lerap measurement protocol and analysis methodology
To identify options for harmonisation with other European drift-reduction schemes.

Specific objectives:
1. Relate wind tunnel measurements of drift to the levels of drift reduction that are achieved under field conditions, taking account of uncertainty and variability (Year 1)
2. Identify appropriate wind tunnel protocols, measures and analyses that provide the best correlation with drift reduction in the field (year 2)
3. Revise measurement protocols and analysis methodology to incorporate new measures and allow greater flexibility (year 3)
4. Consider options for harmonization with other European drift-reducing schemes (years 1 – 3)
5. Publish the findings in the open literature and report (year 3)
Time-Scale and Cost
From: 2013

To: 2015

Cost: £75,210
Contractor / Funded Organisations
Pesticide use              
Fields of Study
Pesticide Safety